Powered operator access system

ABSTRACT

An access ladder configurable from an extended position for providing access to a structure and a stowed position. The access ladder comprises an elongated first member having a first step extending laterally therefrom. An elongated second member is associated with the first member and configured for translational movement relative thereto and has a second step extending laterally therefrom. A link extends between the second member and the structure such that rotation of the first member moves the second member translationally relative to the first member, thereby moving said at least one second step towards said at least one first step.

TECHNICAL FIELD

This patent disclosure relates generally to access systems and, moreparticularly to systems for accessing operator stations of machines.

BACKGROUND

Many machines have operator controls located a distance from the ground.For example, large machines, such as large construction machines andlarge mining machines, often include cabs containing operator controlsthat are located atop the machines several feet from the ground. Inorder to access the controls, an operator needs the ability to ascendthe distance from the ground to the cab. Many machines include accesssystems to aid the operator in accessing the controls of the machine.For instance, many machines include ladders, ramps, stair steps, and thelike.

In many instances, machines must traverse rough terrain during theiroperation. For instance, wheel tractor scrapers, trucks, excavators,loaders, and other machines often pass over rough, ungroomed or unpavedground of a construction or mining site. As a result, a large distance,often several feet, between the ground and the machine is desirable toallow the machine to pass over the terrain without hindrance or damage.In addition, large machines must pass vegetation, structures, and othermachines while traversing a work site. Therefore, it is desirable thatany access system provide adequate clearance to the ground and notproject outwardly when the machine is in use, so as to avoid unintendedcontact with external objects.

SUMMARY

The disclosure describes, in one aspect, a ladder for access to astructure and egress therefrom, the ladder configurable from a firstextended position for providing access to the structure and a secondstowage position for storing the ladder when not in use. The laddercomprises an elongate upper member rotatably connected at an upper endto the structure at a connector and at least one upper step extendinglaterally from the upper member. An elongate lower member is attached tothe upper member and configured for translational movement relative tothe upper member. At least one lower step extends laterally from thelower member. The ladder includes a link extending between the lowermember and the structure such that upward rotation of the upper memberfrom the extended position to the stowage position causes the lowermember to move translationally relative to the upper member, therebymoving said at least one upper step towards said at least one lowerstep.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of a machine in accordance with anembodiment;

FIG. 2 is a side perspective view of an access system of the machine ofFIG. 1 with the access system in an extended position;

FIG. 3 is side a perspective view of the access system of FIG. 2;

FIG. 4 is a side perspective view of the access system of FIG. 2, shownin greater detail;

FIG. 5 is a rear perspective view of the access system of FIG. 2;

FIG. 6 is side view of the access system of FIG. 2, with the accesssystem in an extended position;

FIG. 7 is a side view of the access system of FIG. 6, having a ladderportion rotated slightly towards a stowage position;

FIG. 8 is a side view of the access system of FIG. 7, shown with theladder rotated further towards the stowage position; and

FIG. 9 shows a side view of the access system of FIG. 8, with the ladderin the stowage position.

DETAILED DESCRIPTION

This disclosure relates to powered access systems providing ingress andegress to operator stations of machines.

In the following description, various embodiments of the presentdisclosure will be described. For purposes of explanation, specificconfigurations and details are set forth in order to provide a thoroughunderstanding of the embodiments. However, it will also be apparent toone skilled in the art that the present disclosure may be practicedwithout the specific details. Furthermore, well-known features may beomitted or simplified in order to focus on the embodiment beingdescribed.

Referring now to the drawings, in which like reference numeralsrepresent like parts throughout the several views, FIG. 1 shows amachine 20 in accordance with an embodiment. As shown in the drawings,the machine 20 can be a wheel tractor scraper, which is a machine thatscraps dirt, clay, or other material from the ground in order to bringthe ground to a desired grade, such as for a road. The machine 20 can beanother type of machine, such as an articulated or other truck, abackhoe loader, a cold planer, compactor, feller buncher, forestmachine, a forwarder, harvester, excavator, loader, knuckle boom loader,material handler, loader grader, multi-terrain loader, off-highwaytractor, off-highway truck, a paving machine, a pipe layer, a roadreclaimer, a scraper, a skid-steel loader, a skidder, a telehandler,track loader, track-type tractor, wheeled dozer, wheeled excavator,wheeled loader, or an underground machine, or any other type of machine.The machine 20 can be mobile, but it can also be stationary without theability to move from one location to another.

In the embodiment shown in the drawings, the machine 20 includes a cabportion 22 (also referred to as a tractor portion) and a bed portion 24(also referred to a hopper, scraper, or bowl portion, the hopper or bowlreferring to a receptacle for material scraped into the bed portion 24),both of which are supported by a plurality of wheels 26. The cab portion22 in an embodiment is configured for operating the machine 20. In anembodiment, the cab portion 22 includes a cab 28 housing operatorcontrols of the machine 20. The cab 28 can sit in front of one of a pairof opposing fenders 30, each fender 30 extending over a wheel 26 onopposing sides of the cab portion 22. A bumper 32 extends from a frontside of each fender 30 around a hood 34 for housing an engine of themachine 20. In an embodiment, the bumper 32 projects outwardly to forman upper surface of the bumper 32 shared with an upper surface of aledge 35 extending laterally from a side of the hood 34 in front of thefender 30. An access system 36 for providing access to and egress fromthe cab 28 by use of a ladder, as described in more detail below, isconnected to the ledge 35, although the access system 36 can be locatedat any suitable portion of the machine 20 such as in front of the fender30 closest to the cab 28. Access systems such as the access system 36shown, can be located in multiple locations of the machine 20. Ahandrail 38 projecting upwardly from the ledge 35 or other suitablelocation can be located in close proximity to the access system 36 toprovide leverage to an operator utilizing the access system 36 byallowing the operator to grip the handrail 38 for leverage.

As shown in FIG. 2, the ledge 35 includes two recesses 40 spaced onefrom the other. As shown in the drawing, the access system 36 includes aleft upper member 42 and a right upper member 44, each rotatablyconnected to the machine 20 at one of the recesses 40. In an embodiment,the left upper member 42 is an elongate bar of metal or other suitablematerial extending to form an “L” shape, the shorter leg of the “L”extending towards the machine 20 at an angle, such as approximatelyninety degrees, to the longer leg of the “L.” The right upper member 44is similarly configured to the left upper member 42 and extends adistance from and parallel to the left upper member 42. As shown in FIG.2, the access system 36 is in an extended configuration whereby theaccess system 36 is configured as a ladder, with both the left uppermember 42 and right upper member 44 extending downward and away from theledge 35. From this position, the access system 36 can be used foraccessing the cab 28, as described more fully below.

FIG. 3 shows the access system 36 in a stowage configuration whereby theleft upper member 42 and right upper member 44 have been rotatedupwardly about a left hinge 46 or other connector located in one of therecesses 40 and right hinge 48 or other connector located in the otherrecess 40, respectively, so that the left upper member 42 and rightupper member 44 extend upwardly from the left hinge 46 and right hinge48 respectively.

FIG. 4 shows the access system 36 in greater detail. In an embodiment,the left upper member 42 and right upper member 44 extend parallel toone another with a plurality of steps 50 extending parallel andhorizontally between them, thereby collectively forming an upper ladderportion. While the drawings show two steps 50 extending between the leftupper member 42 and right upper member 44, only one step 50 or more thantwo steps 50 can extend between the left upper member 42 and right uppermember 44. For instance, should a longer access system 36 be necessaryfor a particular machine, a longer left upper member 42 and right uppermember 44 can be provided with several steps 50 extending between them.Likewise, should a shorter access system 36 be necessary for aparticular machine, a shorter left upper member 42 and right uppermember 44 can be provided with only one step 50 extending between them.The steps 50 can be an elongate structure of material, such as metal,able to support the weight of an operator of the machine 20.

In an embodiment, the access system 36 includes a left lower member 52extending from a lower end of the left upper member 42. Similarly, theaccess system 36 includes a right lower member 54 extending from a lowerend of the right upper member 44. In an embodiment, the left lowermember 52 is an elongate bar of material configured to fit within theleft upper member 42 such that the left lower member 52 can slidably andtranslationally move along its long dimension relative to the left uppermember 42. In this manner, the left lower member 52 is able to telescopeout of an end of the left upper member 42, the end being the lower endof the left upper member 42 when the access system is in an accessposition. Nylon plates (not shown) on external faces of the left lowermember 52 or other devices for reducing friction between the left uppermember 42 and left lower member 52 can be included. Moreover, otherconfigurations for configuring the left upper member 42, right uppermember 44, left lower member 52, and right lower member 54 to providefor translational movement between the left upper member 42 and leftlower member 52 and between the right upper member 44 and right lowermember 54 are possible. For example, the left lower member 52 need notextend into the end of the left upper member 42, but can be slidablyconnected to the left upper member 42, such as by a channel welded to aside of the left upper member 42 that has an inner shape correspondingto the outer shape of the left upper member 42, so that the left lowermember 52 is able to slide adjacent to the left upper member 42. Theright upper member 44 and right lower member 54 can be similarlyotherwise configured. The right lower member 54, in an embodiment, issimilarly configured to the left lower member 52.

An extension step 56, such as a step configured similarly to the steps50, can extend between lower ends of the left lower member 52 and rightlower member 54, thereby collectively forming a lower ladder portion.While the drawings show only one extension step 56 extending between theleft lower member 52 and right lower member 54, more than one step canextend parallel between the left lower member 52 and right lower member54, for example, to create an access system 36 with greater length. Theleft upper member 42, right upper member 44, left lower member 52, rightlower member 54, steps 50, and extension step 56 are collectivelyreferred to as a ladder assembly 57 as, when the access system 36 is inan extended access position, the access system 36 functions as a ladder.

As the left lower member 52 and right lower member 54 are connected tothe left upper member 42 and right upper member 44, respectively, theextension step 56 is able to move toward and away from the steps 50 asthe left lower member 52 and right lower member 54 slide relative to theleft upper member 42 and right upper member 44, respectively. In thismanner, the length between the top most step 50 and the extension stepcan be varied and, in particular, made shorter when the access system 36is not in use.

FIG. 5 shows the access system 36 from a rear vantage point with theladder assembly 57 in an access position. In an embodiment, the lefthinge 46 and right hinge 48 are attached to the upper surface of ahorizontally-extending plate 58 of the machine 20, which is attached toan interior portion of the bumper 32 so that each hinge is exposed by arespective recess 40. The left hinge 46 and right hinge 48 canalternatively be attached directly to the bumper 32 or other part of themachine 20 as desired or as warranted by design of the machine 20.

As shown in the drawing, the access system 36 includes a left link 60extending between the machine 20, such as at a location of the plate 58below the left hinge 46, and an upper end of the left lower member 52,thereby providing a link between the upper end of the left lower member52 and the plate 58. In an embodiment, the left link 60 is rotatablyconnected to the plate 58 at one end and rotatably connected to the leftlower member 52 at an opposite end. Generally, the left link 60 canconnect directly to the machine 20, such as by connecting to connector(also referred to as a link connector) attached to a portion of a frameof the machine 20, or the left link 60 can connect to the machine 20indirectly, such as by connecting to a connector located on the plate58, as shown in the drawings, or by connecting to another suitableportion of the access system 36. In an embodiment, the left link 60 isan elongate strip of metal or other rigid material, although it can alsobe a ribbon of flexible or other material. In an embodiment wherein theleft lower member 52 extends into an end of the left upper member 42,the left upper member 42 includes a left slot 64, which is a slotextending through a portion of a surface of the length of the left uppermember 42, so as to allow the left link 60 to pass through the leftupper member 42 to the left lower member 52. A right link 62 isconfigured similarly to the left link 60, extending from the right hinge48, through a right slot 66 extending along a portion of the length ofthe backside of the right upper member 44, to an upper end of the rightlower member 54.

In an embodiment, one of the upper members, such as right upper member44, includes a lever assembly 68 mechanically engaging the right uppermember 44 at an upper end of the right upper member 44 in front of theright hinge 48. The lever assembly 68 is any device, such as a leverrigidly attached to the left upper member 44, that causes the accesssystem 36 to rotate about the left hinge 46 and right hinge 48 whenforce is applied to the lever assembly 68. As shown in the drawing, inan embodiment, the lever assembly 68 comprises two parallel lever plates70, each cut so as to form an “L” shape with a leg of the “L” extendingupwardly when the access system 36 is in an access position, as shown inFIG. 5. The lever plates 70 extend parallel to one another on oppositesides of the upper end of the right upper member 44 and mechanicallyengage the right upper member 44, such as with tabs (not shown)extending beneath or into the sides of the right upper member 44. In analternate embodiment, the lever assembly 68 and right upper member 44 orleft upper member 42 form a unitary component of the access system 36. Alever bar 72, which can be an elongate bar of metal, extends between thelever plates 70 above the upper end of the right upper member 44.

In an embodiment, an actuator 74 engages the lever bar 72 and extendsfrom the lever bar 72 toward an interior of the machine 20, where it isrigidly attached to an appropriate structure of the machine 20, such asan internal frame component of the machine 20, as shown more clearly inFIG. 4. In an embodiment, the actuator 74 is an electric linearactuator, although it can also be a linear hydraulic cylinder assemblyor another type of actuator. Generally, the actuator 74 is any devicecapable of applying a force to an appropriate component of the accesssystem 36 so as to rotate the left upper member 42 about the left hinge46 and the right upper member 44 about the right hinge 48. The actuator74 need not apply a linear force, but can also utilize rotational orother force according to a particular embodiment. In addition, theactuator 74 can also include a torque limiter or other mechanism forensuring that the actuator 74 does not apply more force than desired.

FIGS. 6 through 9 demonstrate how, in accordance with an embodiment, theaccess system 36 is moved from an access configuration (also referred toas an access position or extended position), as shown in FIG. 6, to astowage configuration (or stowage position), as shown in FIG. 9.

Referring specifically to FIG. 6, in the access position, the ladderassembly 57 is oriented with the left lower member 52 and right lowermember 54 extending downwardly from the left upper member 42 and rightupper member 44, respectively. In an embodiment, the ladder assembly 57extends downward and slightly away from the machine 20, when in theaccess position. The extension step 56 is spaced from the lowermost step50 enough to allow an operator to place his or her foot atop theextension step 56, but close enough so that the operator can step fromthe extension step 56 to the lowermost step 50.

As shown by comparing FIGS. 6 and 7, when the actuator 74 contracts, forexample after actuation of an electric switch (not shown) by theoperator, the actuator 74 pulls the lever assembly 68 towards themachine 20, thereby causing the ladder assembly 57 to rotate upwardlyabout the left hinge 46 and right hinge 48. As the ladder assembly 57rotates upwardly, the distance between the lower end of the right uppermember 44 and the connection of the right link 62 to the machine 20increases. Consequently, the right link 62 pulls the right lower member54 further into the right upper member 44, thereby causing the extensionstep 56 to approach the steps 50. As shown by further comparing FIG. 8,as the actuator 74 contracts further, the left lower member 52 and rightlower member 54 extend further into the left upper member 42 and rightupper member 44, respectively, bringing the extension step 56 closer tothe step 50 closest to the extension step 56.

As shown in FIG. 9, when the actuator 74 has fully contracted, theladder assembly 57 has rotated approximately 180 degrees from the accessposition to the stowage position, wherein the ladder assembly 57 extendsupwardly from the ledge 35, with the ladder assembly 57 oriented withthe left lower member 52 and right lower member 54 extending upwardlyfrom the left upper member 42 and right upper member 44, respectively.In addition, by moving the access system 36 completely to the stowageposition, the left link 60 and right link 62 have pulled the left lowermember 52 and right lower member 54 nearly completely into the leftupper member 42 and right upper member 54, respectively, so that theextension step 56 is adjacent the closest step 50, which is theuppermost step 50 shown in FIG. 9. Consequently, in the stowageconfiguration, the access system 36 is more compact than in the accessconfiguration. In addition, the access system 36, in the stowageconfiguration, does not have any components extending laterally from themachine 20 or below the machine 20, thereby reducing any likelihood thatthe access system 36 may come in contact with the ground or anotherobject or person when the machine 20 is in motion. If a machine containsmoving parts, such as a hydraulically-operated boom or rotating cab,moving the access system 36 to the stowage position can also provide forfree movement of any moving parts whereas the access system 36 mayinterfere with movement when in the access position.

Operation of the access system 36 from the stowage configuration to theaccess configuration is achieved similar to operation of the accesssystem 36 from the access configuration to the stowage configuration,with the process proceeding in reverse. In particular, upon activationof a switch or other device, the actuator 74 pushes the lever bar 72,causing the ladder assembly 57 to rotate downward about the left hinge46 and right hinge 48. In an embodiment, while the ladder assembly 57rotates downward, the left link 60 and right link 62 push the left lowermember 52 and right lower member 54, respectively, out of the lower endof the left upper member 42 and right upper member 44, respectively, asthe distance between the lower ends of the left upper member 42 andright upper member 44 and the connections of the left link 60 and rightlink 62 to the plate 58 decreases. In an alternate embodiment, the leftlink 60 and right link 62 are flexible and, consequently, gravity and/oranother external force, such as the force of an operator stepping on theextension step 56, push the left lower member 52 and right lower member54 out of the lower ends of the left upper member 42 and right uppermember 44, respectively, thereby separating the steps 50 from theextension step 56. In yet another embodiment, the access system 36includes only one of the left link 60 and right link 62, which pushesthe corresponding left lower member 52 or right lower member 54 out ofthe end of the corresponding left upper member 42 or right upper member44.

Referring back to FIG. 4, the access system 36 can include featuresadditional to those listed above. For example, in accordance with anembodiment, the access system 36 can include an emergency releaseincluding an emergency release cable 76 and a handle 78. The emergencyrelease cable 76 releases the ladder assembly 57 from the actuator 74 sothat the ladder assembly can be manually placed to the access positionshould the actuator 74 fail or lack a power source. The handle 78provides an operator of the machine 20 a mechanism for pulling theemergency release cable 76, and can be included at a terminal end of theemergency release cable 76 away from ladder assembly 57 and can bemounted on the machine 20 in a convenient location, such as on a portionof the machine 20 that does not frequently move relative to theremainder of the machine 20, for example, on an external body panel ofthe machine 20 behind a door of the machine 20. In an embodiment, thehandle 78 pulls the emergency release cable 76, which releases amechanical connection between the ladder assembly 57 and the actuator74, for example, by pulling one or more components of the lever assembly68 away from the right upper member 44 so as to mechanically disconnectthe lever assembly 68 from the right upper member 44 or from theactuator 74. Generally, any mechanism for allowing manual movement ofthe ladder assembly 57 can be used in connection with the emergencyrelease cable 76 or with another mechanism controlling whether theaccess system 36 is operated manually or by the actuator 74.

INDUSTRIAL APPLICABILITY

When using a machine, an operator must typically ascend to a cabcontaining controls for operating the machine. For example, an operatorof the machine 20 must ascend to the cab 28 of the machine 20 in orderto drive the machine 20 around a job site where the machine 20 is beingused to haul material in the bed portion 24 from one point to another.

To ascend to the cab 28, the operator climbs the ladder portion 57 as ifit were a conventional ladder. In particular, the operator begins bystepping onto the extension step 56 and then systematically ascendingsuccessive steps 50 until reaching the ledge 35. The operator can gripportions of the ladder assembly 57 and the handrails 38, as necessary,to pull himself or herself up. In the embodiment shown in the drawings,as seen in FIG. 1, the operator can climb additional fender steps 80extending upwardly from in front of the fender 30, or otherwise suitablylocated, and ascending the front portion of the fender 30 to access anentrance of the cab 28 or other location on the cab portion 22 of themachine 20. Other ladders, access systems, or mechanisms can be utilizedin connection with the access system 36 in order to ascend a machine.

Upon ascending the machine 20, the operator, in an embodiment, activatesan activation switch (not shown) electrically connected to the actuator74, causing the actuator 74 to rotate the ladder assembly 57 upward tothe stowage position. A safety switch (not shown) and/or alarm may beincluded for preventing the machine 20 from achieving full operationuntil the access system 36 is in the stowage configuration or foralerting the operator that the access system 36 is in the extendedaccess configuration while the machine 20 is in use. With the accesssystem 36 in the stowage configuration, the operator operates themachine 20 until work is complete or until the operator otherwise needsto descend from the cab 28. In order to descend from the cab 28, theoperator activates the activation switch, causing the actuator 74 torotate the ladder assembly 57 downward until the ladder assembly 57 isin the access configuration. The operator then descends the ladderassembly 57 by systematically stepping on successive steps 50 untilreaching the extension step 56 from which he or she makes a small stepor jump to the ground.

It will be appreciated that the foregoing description provides examplesof the disclosed system and technique. However, it is contemplated thatother implementations of the disclosure may differ in detail from theforegoing examples. All references to the disclosure or examples thereofare intended to reference the particular example being discussed at thatpoint and are not intended to imply any limitation as to the scope ofthe disclosure more generally. All language of distinction anddisparagement with respect to certain features is intended to indicate alack of preference for those features, but not to exclude such from thescope of the disclosure entirely unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context.

Accordingly, this disclosure includes all modifications and equivalentsof the subject matter recited in the claims appended hereto as permittedby applicable law. Moreover, any combination of the above-describedelements in all possible variations thereof is encompassed by thedisclosure unless otherwise indicated herein or otherwise clearlycontradicted by context.

1. An access ladder, the access ladder configurable from a firstextended position for providing access to a structure and a secondstowed position, the ladder comprising: an elongated first member havinga first end and a second end and connected to the structure; at leastone first step extending laterally from the first member; an elongatedsecond member associated with the first member and configured fortranslational movement relative to the first member, the second memberhaving at least one second step extending laterally from the secondmember; and a link extending between the second member and the structuresuch that rotation of the first member from the first extended positionto the second stowed position moves the second member translationallyrelative to the first member, thereby moving said at least one secondstep towards said at least one first step.
 2. The access ladder of claim1, including an actuator for rotating the first member between the firstextended position and the second stowed position.
 3. The access ladderof claim 2, wherein the actuator provides a linear force and wherein theaccess ladder further includes a lever attached to the first member, thelever configured to transmit the linear force into rotational movementof the first member.
 4. The access ladder of claim 2, including arelease for mechanically disconnecting the first member from theactuator.
 5. The access ladder of claim 1, wherein the first member ishollow at the second end and wherein the second member is configured toextend from within the second end.
 6. The access ladder of claim 5,wherein the link extends through a slot extending through a surface ofthe first member.
 7. The access ladder of claim 1, wherein the link isconnected to the structure at a link connector and to the first memberat the second end, the first member is connected to the structure at thefirst end, and the link and first member are configured such thatrotation of the first member from the first extended position to thesecond stowed position increases the distance between the second end andthe link connector.
 8. An access system, the access system configurablebetween an access configuration and a stowed configuration, the accesssystem comprising: a first ladder portion having an elongated firstmember from which at least one first step extends horizontally, thefirst ladder portion having a first end and a second end, the first endattached to the structure; a second ladder portion having an elongatedsecond member from which at least one second step extends horizontally,the second ladder portion slidably associated to the first ladderportion so as to extend past the second end; and a link extending fromthe structure to the second ladder portion so as to move the secondladder portion to slide relative to the first ladder portion.
 9. Theaccess system of claim 8, including an actuator for rotating the accesssystem between the access configuration and the stowed configuration.10. The access system of claim 9, wherein the actuator provides a linearforce and wherein the access system further includes a lever attached tothe first member, the lever configured to transmit the linear force intorotational movement of the first member.
 11. The access system of claim9, including a release for mechanically disconnecting the first memberfrom the actuator.
 12. The access system of claim 8, wherein the firstmember is hollow at the second end and the second member is configuredto extend from within the second end.
 13. The access system of claim 12,wherein the link extends through a slot extending through a surface ofthe first member.
 14. The access system of claim 8, wherein the link isconnected to the structure at a link connector, and the link and firstmember are configured such that rotation of the first member from theaccess configuration to the stowed configuration increases the distancebetween the second end and the link connector.
 15. The access system ofclaim 8: wherein the first ladder portion further includes an additionalfirst member attached to the structure at an additional first end, theadditional first member extending parallel to the first member such thatthe first step extends between the first member and the additional firstmember; and wherein the second ladder portion further includes anadditional second member slidably associated with the additional firstmember and configured such that the second step extends between thesecond member and the additional second member.
 16. An off-highwayvehicle, comprising: an access system configurable between an accessconfiguration and a stowed configuration, the access system comprising:a first ladder portion having an elongated first member from which atleast one first step extends horizontally, the first ladder portionhaving a first end and a second end, the first end attached to thestructure; a second ladder portion having an elongated second memberfrom which at least one second step extends horizontally, the secondladder portion slidably associated to the first ladder portion so as toextend past the second end; and a link extending from the structure tothe second ladder portion so as to move the second ladder portion toslide relative to the first ladder portion.
 17. The off-highway vehicleof claim 16: wherein the second ladder portion further includes anadditional first member attached to the structure at an additional firstend, the additional first member extending parallel to the first membersuch that the first step extends between the first member and theadditional first member; and wherein the second ladder portion furtherincludes an additional second member slidably associated with theadditional first member and configured such that the second step extendsbetween the second member and the additional second member.
 18. Theaccess system of claim 17, wherein the additional first member has anadditional second end corresponding to the second end of the firstmember, wherein the second end and additional end are hollow, andwherein the second member and additional second member are configured toextend from within the second end and additional second end,respectively.
 19. The access system of claim 18, further including anadditional link extending between the structure and the additionalsecond member and wherein each of the link and additional link extendsthrough a slot extending through a surface of a corresponding firstmember.
 20. The access system of claim 16, wherein the link is connectedto the structure at a link connector, and the link and first member areconfigured together such that rotation of the first member from theaccess configuration to the stowed configuration increases the distancebetween the second end and the link connector.